A capacitive silicon resonator with a movable electrode structure for gap width reduction

Abstract

This paper presents a capacitive silicon resonator with movable electrode structures to reduce the motional resistance for lower insertion loss and lower phase noise, and also increase the tuning frequency range for the compensation of temperature drift of the silicon oscillator. The resonant frequency of the fabricated device with a length of 500 µm, width of 440 µm and thickness of 5 µm is observed at 9.65 MHz, and the quality factor is 49 000. Using an electrostatically drived movable electrode structure, it is shown that the motional resistance is reduced by 200 times, the output signal (insertion loss) is increased by 21 dB and the tuning characteristic of the frequency is also increased by seven times over that of the structures without movable electrodes.